1. Field of the Invention
The present invention relates to a power generator and more particularly, to a miniature generator, which has a permanent magnet mounted on a tubular shaft inside a carrier and kept by a match in a slightly unbalanced condition for rotation to induce windings of a winding holder upon movement of the carrier by an external force, thereby causing the windings to produce an induction current.
2. Description of the Related Art
Following fast development of technology in the progressive era, the industrial society has been gradually replaced by the knowledge society. In consequence, sophisticated electronic products have been continuously created. Nowadays, human living is not separable from “electricity”. However, facing the crisis of energy shortage, every country around the world is trying hard to crease cost-effective, safe, environmentally protective substitutes having the characteristics of smaller size, lighter weight and higher energy density. Therefore, many miniature generators are created and intensively used in our daily life.
FIG. 4 illustrates a conventional miniature generator A. According to this design, the miniature generator A comprises a housing A1, an annular magnet A2 mounted inside the housing A and fastened to the inside wall of the housing A1, and an armature A3 rotatably mounted in the housing A1 at the center. When rotating the armature A3, a magnetic field effect between the armature A3 and the annular magnet A2 induces a current. The induced current is guided out of the miniature generator A through an electric brush A4 for application.
In actual practice, the aforesaid miniature generator has drawbacks as follows:    1. Because of the armature A3 is formed of a stack of silicon steel plates A31, a magnetic filed effect is produced between the armature A3 and the annular magnet A2 and the armature A3 is attracted to the flowing direction of the magnetic line of force. Therefore, the applied force must overcome the magnetic attractive force before rotating the armature A3, resulting in a big loss of energy.    2. The electric brush A4 is disposed at the top side of the armature A3 and electrically connected with the armature A3 for output of induced current. The electric brush A4 starts to wear after a long use. When the electric brush A4 starts to wear, the voltage will be relatively reduced and will become unstable, shortening the working life of the miniature generator A.
Therefore, it is desirable to provide a miniature generator that eliminates the aforesaid drawbacks.